Julian Brazier is a former Defence Minister, and was MP for Canterbury from 1987-2017.

Most commentators agree that the sad and diminishing housing prospects for young people played a key role in setting the conditions for the recent general election swing against the Conservative Party and a wider loss of faith in capitalism. The collapse in home ownership levels now extends to people well into their thirties, and the spiralling cost of renting has driven many back to the parental home following university – or after a first attempt to fly the nest with a job.

At the same time as that consensus is emerging, an almost wholly separate debate is raging among Conservatives as to how much we should control immigration. Voices tend to split between, on the one hand, those who focus on the huge contribution of so many individual immigrants – people who have become our friends and co-workers. On the other are those concerned about the impact of unprecedented numbers of incomers on infrastructure and cohesion.

In a country in which nearly all the political establishment and commentariat finished their education in literary rather than numerate disciplines, it should be no surprise that those who base their arguments on people are winning the discourse in the public space over those who calculate the effects of numbers on a rate of population growth unknown for generations. It is not so much that discussing immigration is seen as racist: it is more that scrutinising the impact of swollen numbers on social problems – including housing shortages – is seen to be unfairly stigmatising incomers.

The result is that articles on housing policy seldom mention the role of immigration in swelling demand, nor question the need to reduce it in order to ease the competition for accommodation. Instead, they focus almost exclusively on how to boost the supply of homes, whether by providing more land, directly incentivising more building, or by making it easier for people to buy. It is certainly true that building dropped to pitiful levels under the last Labour government, and is only slowly recovering; but the principal factor in the housing crisis has been a rise in population unparalleled since the Victorian era. Then, successive governments adopted measures to encourage emigration. Such was the consensus that rapidly rising population was a threat to living conditions that some of those programmes lasted until the 1960s.

The ONS says that the lion’s share of recent measured population growth, 62.4 per cent, comes from unprecedented levels of so-called ‘net’ (legal) migration; but behind the calculation of those net figures is the counting of elderly Brits retiring abroad against young incomers. This further boosts the impact of migration on population, but appears under domestic fertility growth, not net migration, in the statistics. The ONS projects that the UK’s population will reach 70 million by 2026 – a huge rise of nine million, or 15 per cent, in just 20 years.

Yet the ONS has consistently under-forecast population growthmin successive projections over the past generation. In part, this is because there is a growing population of illegal migrants, mostly people overstaying visas. The ONS suggests that the population is rising at a staggering half a million per year, but its surveys do not tend to pick up these illegal residents. Indeed, proxy measures, such as GP registrations and school rolls, point to substantial underestimates by ONS in parts of the country, showing that growth is even higher than their statistics suggest.

The Government has taken a number of steps to promote housebuilding and needs to do more, but a colossal building programme is already needed just to tread water against this spiralling demographic growth. It is worth dwelling on that point for a moment: a very large building programme will be required just to stop housing shortages from getting worse, even if we were to restrain population growth only to that which is now built into our current population. The children in our overcrowded primary schools will be adults in half a generation, needing housing – even though, in some areas, many of their families do not appear in ONS surveys.

Surely the yardstick against which migration should be measured is not current cost/benefit economic measures but the capital cost, in housing and infrastructure shortages, caused by rapidly rising population. Of course, we need people with key skills – and want students who are the brightest and the best – but the continuing inflow of unemployed and low-skilled people from Europe (the majority of EU migrants last year were either unemployed or unskilled), together with the granting of visas to overseas incomers who are likely to overstay, is fuelling a population spiral, which really is unsustainable.

In recognising this, Theresa May and her supporters in Cabinet have taken on two powerful lobbies: business and the universities. Business is wedded to high migration to keep its costs down. But modest labour shortages drive up wages and productivity, as firms are forced to invest. Such a shift would bring the prospect of gaining a home – even buying one – within reach of many people who have no prospects today and now look to socialism to offer hope.

The issue with universities is also about narrowly defined self-interest. We should be proud of Britain’s best universities and their places in international ranking tables, but we must also recognise that too much of higher education has become a business, in which income maximisation is the key driver. The willingness of many universities to suck in domestic students without the tools to benefit from their courses shows this. (The admission of Engineering students without Maths A levels, and English undergraduates who cannot craft a grammatical sentence, are surely at least as worrying as those reading apparently superficial subjects).

We need to assert that there is no contradiction between seeking to continue to attract the brightest and best students from around the world, and taking a hard look at high risk visa applicants – including less able candidates from poor countries. How many students actually stay is hotly debated, but a study by ONS last year  suggested that, in recent years, it is over half of students, indeed up to a quarter of total UK net migration. The study comes with caveats – including the fact that there is no way of matching cohorts – and has been challenged by organisations like the IPPR and the universities themselves – but it does at least show that there are good grounds for believing that many students do stay on.  Those who stay will need housing and many will wish to bring in family members. Yet there are many even within the Conservative Party who have signed up to the university lobby’s view that we should jettison the internationally agreed measure of population movements and take students out of immigration data altogether – presumably whether they stay or not.

Behind the policy problem of rising population and its baleful impact on our overcrowded country is a political problem. An unholy alliance of vested commercial interests on the one hand, and left-leaning commentators on the othe,r have poisoned the well of the debate on immigration. We have to reclaim the high ground by pointing out that it is not an attack on individual immigrants to say that our housing and infrastructure are gravely over-stretched in large parts of the UK. We must shift the focus of discussion on immigration, including on the negotiations with the EU, from current cost/benefit analysis to the more important (because more permanent) capital factors. We must challenge economists who measure the impact of migration by counting tax paid against benefits received, but ignore the fact that people are left without homes and fail to question whether roads, railways, water supply, sewers etc are becoming overloaded.

Representing the constituency with by far the largest number of students in the UK for 30 years, only to lose it in June, I experienced at first hand the impact of our lack of a national message for young people. Part of that message must be to offer them the real prospect of homes as good as their parents. That has to involve challenging the vested interests and commentators who suggest that this can be done while the current population spiral continues, fed by mass migration. For a generation reared on an ideology which equates any discussion of immigration with racism, it is not going to be an easy sell. Nevertheless, if we shy away from the fight, and continue to ignore the impact of immigration on the prospects of our next generation gaining the homes they want, we – and the country – will pay a dreadful price.